Invasive “imaging”wes-rotterdam.nl/symposium_2010_files/Radiologie nieuwe 3d beelden van... ·...

WESCARDIALE CT

11 maart 2010

M.L. DijkshoornErasmus MC Rotterdam 1

Het Hart in Beeld11 maart 2010

Marcel Dijkshoorn Research CT [email protected]

Invasive “imaging”Invasive “imaging”

Andreas Vesalius

Humani corporis fabrica libri septem 1543

First Nobel Prize in Physics: 1901

Wilhelm Conrad Röntgen

Discovery of X-rays, November 8, 1895

Non-invasive imagingNon-invasive imaging

Röntgen’s lab

X-ray, 22 dec, 1895

Modern Chest X-ray

Electro magnetic spectrumElectro magnetic spectrum

First commercial CT EMIFirst commercial CT EMIFirst CT scan 1972: G.N. Hounsfield & A.M. CormackNobel prize 1979

WESCARDIALE CT

11 maart 2010


Natural radiation & risk estimationNatural radiation & risk estimation

Natural radiation NL: +/- 2mSv

5 / 100.000Average

1 / 100.000Adolescent (80y)

2 / 100.000Adolescent (60y)

3,5 / 100.000Adolescent (30-40y)

7,5 / 100.000Adolescent (20-30y)

18 / 100.000Adolescent (10-20y)

14 / 100.000Child (0-10y)

Lifetime risk of

death / mSv

Age

Estimated risk by age

Medical radiation doseMedical radiation dose

Basic principle CT-scanBasic principle CT-scan

Measure the slice x-ray absorption profile under multiple anglesMeasure the slice x-ray absorption profile under multiple angles

Image reconstructionImage reconstruction

Calculate x-ray absorption for small volumes in slice

Image quality depends on: patient, scanner type, indication, protocol & radiation

Calculate x-ray absorption for small volumes in slice

Image quality depends on: patient, scanner type, indication, protocol & radiation

Calcium ScoreCalcium Score

Scan without contrast

Measures amount of

calcium

Powerful risk factor

! No diagnosis !

Predictor of

successful CCTA

Scan without contrast

Measures amount of

calcium

Powerful risk factor

! No diagnosis !

Predictor of

successful CCTA

Contrast resolution & intravenous contrastContrast resolution & intravenous contrast

native delay 30sec. delay 80 sec.

WESCARDIALE CT

11 maart 2010


Blooming of calcium and stentsBlooming of calcium and stents

Wide window/greyscale reduces blooming

Wide window/greyscale reduces image contrast

High contrast flow rate’s require large lumen venflon’s

! Injector pressures up to 300 PSI = 15500mm Hg !

Wide window/greyscale reduces blooming

Wide window/greyscale reduces image contrast

High contrast flow rate’s require large lumen venflon’s

! Injector pressures up to 300 PSI = 15500mm Hg !

600/100600/100 800/200800/200 2000/3502000/350 Courtesy of University Clinic of Grosshadern, Munich, Germany

Influence of slice thickness on image quality Influence of slice thickness on image quality

Less than 0.5mm resolution is needed for

good evaluation of small coronary side

branches. (resolution DSA 0.1mm)

Less than 0.5mm resolution is needed for

good evaluation of small coronary side

branches. (resolution DSA 0.1mm)

Spatial resolutionSpatial resolution

Developments in spatial resolutionDevelopments in spatial resolution

4-Slice 64-Slice4-Slice 64-Slice

PatentPatent IntimaIntimaHyperplasiaHyperplasia

OccludedOccluded

Limitations of spatial resolution in 4-Slice is clearly seen when evaluating

stents.

Limitations of spatial resolution in 4-Slice is clearly seen when evaluating

stents.

Motion in non ECG gated scansMotion in non ECG gated scans

4-slice4-slice 16-slice

ECG-synchronizationECG-synchronization

We know the heart has periods of motion and rest. We know the heart has periods of motion and rest.


We can measure the electric signal

With the measured ECG we can estimate the rest period

We can measure the electric signal

With the measured ECG we can estimate the rest period

ECG

WESCARDIALE CT

11 maart 2010


1 2 43

ECG-synchronization ECG-synchronization

70% R-R interval

X-ray High doseLow dose

4-slice CT

35-45 s3mm slice

20-25 s30-35 s

64-slice CT

12 s20 s

Total scantimeTotal scantime

Older scanners:

• Large contrast media volumes

• Long breath holds

• Problems with HR variabillity

Older scanners:

• Large contrast media volumes

• Long breath holds

• Problems with HR variabillity

16-slice CT 128 - 320-sliceDual-Source CT

0.3-5 s0.7-10 s

Cor:Thorax:

30%0% 10% 20% 40% 50% 60% 70% 80% 90%

ECG-Gating

Reconstruction at different %of R-R interval

Optimal atend-systole &end-diastole

Image reconstruction Image reconstruction


After reconstruction all stacks form a volume

Keep in mind between stacks there is a time and heart beat difference

After reconstruction all stacks form a volume

Keep in mind between stacks there is a time and heart beat difference


Stack misalignment is caused by:

• Breathing

• Abdominal motion

• Small differences in heart orientation between beats

• Heart rate variability & inaccurate phase reconstruction

Stack misalignment is caused by:

• Breathing

• Abdominal motion

• Small differences in heart orientation between beats

• Heart rate variability & inaccurate phase reconstruction

WESCARDIALE CT

11 maart 2010


ß-blockers needed to reduce HR ß-blockers needed to reduce HR

HR 45HR 45

HR 75HR 75

165 ms

165 ms

165 ms

165 ms

165 ms

165 ms

165 ms

165 ms

HR 60HR 60

82 ms

82 ms

82 ms

82 ms

Decrease HRDecrease HR

Improve scannerImprove scanner

Dual Source CT achieves a high constant temporal resolution of 75ms

2*90° of both array’s is put together for an 180° image reconstruction.

Dual Source CT achieves a high constant temporal resolution of 75ms

2*90° of both array’s is put together for an 180° image reconstruction.

Dual Source techniqueDual Source technique

75ms75ms

SpaceShuttle

9-12G-force

Dual Source CT: 2 Tubes & 2 Detectors, 2800Kg +/- 40G-force

Single Source scanners:

• Reliable scans up to +/- HR 65

• Success rate decreases and dose increases for higher HR’s

Dual Source scanners:

• Reliable and low dose for all regular HR’s

Single Source scanners:

• Reliable scans up to +/- HR 65

• Success rate decreases and dose increases for higher HR’s

Dual Source scanners:

• Reliable and low dose for all regular HR’s

Temporal resolutionTemporal resolution

HR 49HR 49HR 67HR 67HR 82HR 82Single Source

3D: Coronary Artery Anatomy3D: Coronary Artery Anatomy

64 slice +/- 20 mSv64 slice +/- 20 mSv

3D: Coronary Artery Anatomy3D: Coronary Artery Anatomy

64 slice +/- 20 mSv64 slice +/- 20 mSv

WESCARDIALE CT

11 maart 2010


Example prox. LAD stenosisExample prox. LAD stenosis 64-slice CT coronary angiography64-slice CT coronary angiography

Left Main StenosisLeft Main Stenosis Left Main StenosisLeft Main Stenosis

Left Main Stenosis - post stentLeft Main Stenosis - post stent Left Main Stenosis - post stentLeft Main Stenosis - post stent

WESCARDIALE CT

11 maart 2010


Limitations: Severe calcificationsLimitations: Severe calcifications Aneurysmatic coronariesAneurysmatic coronaries

6 6

Dual Source: Stent RCADual Source: Stent RCA

Dose: 4,3mSv Dose: 4,3mSv

Functional ImagingFunctional Imaging

Ejection fraction

Wall thickening

Wall Motion

Valve motion

Ejection fraction

Wall thickening

Wall Motion

Valve motion

1

7

13

17

15

10

4

28

39

14 16

115

126

Valve stenosisValve stenosis Valves: Fibro elastomaValves: Fibro elastoma

WESCARDIALE CT

11 maart 2010


Pericarditis with valve dislocationPericarditis with valve dislocation DissectionDissection

+/- 20 mSv +/- 20 mSv

MixomaMixoma

Dual Source

+/- 15 mSv

Dual Source

+/- 15 mSv

Diagnostic image qualityDiagnostic image quality

Diagnostic performance of 64-slice CCTA versus conventional

coronary angiography.

• Good results are achieved with low exclusion %.

• However results are achieved in HR controlled patient groups.

Diagnostic performance of 64-slice CCTA versus conventional

coronary angiography.

• Good results are achieved with low exclusion %.

• However results are achieved in HR controlled patient groups.

Excl.

(%)

0

12

0

0

4

1.2

Excl.

(%)

0

12

0

0

4

1.2

64-slice

Leschka, Eur

Heart

Raff, JACC

Mollet,Circulation

Leber, JACC

Ropers, AJC

Schuijf, AJC

64-slice

Leschka, Eur

Heart

Raff, JACC

Mollet,Circulation

Leber, JACC

Ropers, AJC

Schuijf, AJC

N

segments

1005

1065

725

725

1083

842

N

segments

1005

1065

725

725

1083

842

Sens

(%)

94

86

99

76

93

85

Sens

(%)

94

86

99

76

93

85

Spec.

(%)

97

95

95

97

97

98

Spec.

(%)

97

95

95

97

97

98

PPV

(%)

87

66

76

75

56

82

PPV

(%)

87

66

76

75

56

82

NNP

(%)

99

98

100

97

100

99

NNP

(%)

99

98

100

97

100

99

Diagnostic image qualityDiagnostic image quality

Diagnostic performance of 64-slice Dual Source CCTA versus

conventional coronary angiography.

• Results are achieved without heart rate control.

Diagnostic performance of 64-slice Dual Source CCTA versus

conventional coronary angiography.

• Results are achieved without heart rate control.

Excl.

(%)

0

0

1,4

Excl.

(%)

0

0

1,4

Dual Source

Weustink et al,

J Am Coll Cardiol.

Scheffel et al,

Eur.Radiology

Dual Source

Weustink et al,

J Am Coll Cardiol.

Scheffel et al,

Eur.Radiology

N

1489*

100*

420*

N

1489*

100*

420*

Sens.

(%)

95

99

96

Sens.

(%)

95

99

96

Spec.

(%)

95

87

98

Spec.

(%)

95

87

98

PPV

(%)

75

96

86

PPV

(%)

75

96

86

NNP

(%)

99

95

99

NNP

(%)

99

95

99

* segment based* patient based

* segment based* patient based

Dose overviewDose overview

128-slice Dual Sourcelow stable heart rate (prospective hight pitch spiral) 0.5-1.8mSv nomedium & high heart rate (prospective axial) 1.2-5mSv yes

WESCARDIALE CT

11 maart 2010


Dual Source: Coronaries+BypassDual Source: Coronaries+Bypass

Dose: 3,8 mSv Dose: 3,8 mSv

Low risk - Low DoseLow risk - Low Dose

CaSc = 0

75ml contrast

0.59mSv

CaSc = 0

75ml contrast

0.59mSv

ScreeningScreening

50ml contrast

1.1mSv

<1,5s

No breath hold

50ml contrast

1.1mSv

<1,5s

No breath hold

PediatricsPediatrics

3Kg

1.1mSv

No sedation

4ml contrast

3Kg

1.1mSv

No sedation

4ml contrast


3Kg

1.1mSv

No sedation

4ml contrast

3Kg

1.1mSv

No sedation

4ml contrast

WESCARDIALE CT

11 maart 2010



3Kg

1.1mSv

No sedation

4ml contrast

3Kg

1.1mSv

No sedation

4ml contrast

Only 45% of patients with an abnormal CTCA have abnormal myocardial perfusion imaging (MPI) compared to SPECT. Of patients with obstructive coronary artery disease (CAD) on

CTCA, 50% still have normal MPISchuijf JD et al (2006), JACC

Myocardial perfusion imaging (MPI) and CTCA provide different and complementary

information on CAD: detection of atherosclerosis versus detection of ischemia

Discrepancy between CTCA and SPECT.

A B C

D

Myocardial PerfusionMyocardial Perfusion

Future developmentsFuture developments

CT myocardial perfusion

• Anatomy and (stress) function

• Fast

• Non-invasive

• Low radiation

CT myocardial perfusion

• Anatomy and (stress) function

• Fast

• Non-invasive

• Low radiation

Cardiac CT: Diagnostic modality of the future !Cardiac CT: Diagnostic modality of the future !

Invasive “imaging”wes-rotterdam.nl/symposium_2010_files/Radiologie nieuwe 3d beelden van... ·...

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